Well im no pro but ive always been taught to do retouching first, then color. Especially since color might more often when the client wants something changed than a retouch will.

So my basic workflow is:

developing (ie. get the exposure/skintones right for the subsequent retouch)
skin-retouching (DB, Cloning, Reshaping, whatever is needed
contrast & color (order here depends on what should be done when etc).

Sometimes though you will in the color & contrast part note that retouch issues that wasnt obvious before become very apparent so you may have to go back and fix that before continuing with the color work.

This is my workflow and allthough im sure others will have different flow, this have worked for me.

Vapour,
In my experience, much depends on the quality of the image. In forums like this, many people will grab a not-so-good image and retouch it. In that instance, color correction is a vital first step to ensure the d&b and other tools work correctly with adjacent pixels. Additional minor changes to color can always be made later to satisfy your own artistic touches, or whatever.

On the other hand, if you are a photographer (or work with one) and have high quality images to start with, color correction often is not necessary. Slight tweaks to exposure, etc, maybe. In that case, hold any additional color modifications to the end... as HuBBa said, depending on what the client and you discuss.

If you are going to spend 2-3 hours doing a dodge and burn...then I would get all the levels balanced and the colors corrected first...nearest I could...just in case these changes also changed your burning work in some manner afterward. I would hate to disturb those small hard won pixels... and loose that time.

After I balanced first, then retouched...then everything would be in place to come in again...do a snapshot... and then do a second color balancing on that unified base image.